Sepsis is an inflammatory response induced as a lipopolysaccharide (LPS) that is an ingredient of a cell wall acts as a toxin to activate the immune system in a living body excessively when the living body is infected with pathogenic gram-negative bacteria, and causes infections throughout the whole body or is often accompanied by shock when its symptoms are severe. Specifically, the sepsis often develops when hosts who are low resistant to humoral immunodeficiency or cellular immunodeficiency, such as patients, the aged, or premature babies who suffer from basal diseases such as malignant tumors, leukemia, malignant lymphoma, acquired immunodeficiency syndromes (AIDSs), collagen diseases, renal failure, liver diseases, cerebrovascular disorders, diabetes, and the like, undergo treatment and surgery such as chemiotherapy using adrenal steroids or anti-tumor agents, radiotherapy referred to as cobalt radiation, or indwelling catheter, blood dialysis, organ transplantation, heart surgery, and the like. Sepsis is a primary cause of death of hospital patients in the intensive care unit (ICU), and is a very serious disease since its mortality usually amounts to 30% or more. In spite of the development of medical technology, the patients are often infected from the aftereffect following the surgery, and still develop sepsis all over the world. Also, when peoples, such as newborn infants or the aged, which have weaker immune systems in the body, become infected, they often develop into sepsis. As one representative example, mature infants are known to develop neonatal sepsis at a rate of 3/1,000 cases, and premature babies are known to have an incidence rate 3 to 4 times higher than the mature infants. When a patient suffers from sepsis, the patient is generally treated with an antibiotic. However, when pathogens grow highly due to the delay of proper treatment or when a patient is infected with a strain strongly resistant to the antibiotic, the effective treatment cannot be achieved using only the antibiotic. With regard to a gradual increase in pathogens resistant to various antibiotics, the treatment of sepsis or septic shock has emerged as a very important issue. However, a proper therapeutic agent for treating sepsis or septic shock remains to be developed.
The present inventors have made intensive studies to meet the above-described requirements, and found that an ADK protein derived from Mycobacterium tuberculosis binds to LPS to show an excellent therapeutic effect against sepsis. Therefore, the present invention has been completed, based on these facts.